BMW Coolant Expansion Tanks for BMW 3 Series E46 (1999-2005)

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On certain models, namely E36, E46, and E90, the factory BMW expansion tank is prone to either breaking at connection points or blowing apart altogether. If you're starting to feel like your expansion tank is on borrowed time, it's probably time to replace with either a direct OE replacement, or strengthen your cooling setup with an aluminum expansion tank - we offer numerous performance upgrades for your expansion tank. Especially if you're someone who likes to track your BMW, we recommend upgrading your expansion tank to avoid ruining your track day.
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Bav Auto Coolant Expansion Tank - E53 X5, E46, E83 X3
Bav Auto Coolant Expansion Tank - E53 X5, E46, E83 X3
10X Entries Into Our F80 M3 Sweepstakes
Bavarian Autosport - Corporate Logo
T#:640496
Part#: 17137787039
In Stock
Sale - Save 18% $ 61.99

This product was last offered at the strikethrough price on
05-03-2026

$ 50.99 USD
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Sale - Save 18%
$ 61.99

This product was last offered at the strikethrough price on
05-03-2026

$ 50.99 USD
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We have found that the expansion tanks should be replaced based on age as well as condition. Expansion tanks seem to have a lifespan of less than six years before they show signs of fatigue and wear. Pre-emptively replacing the expansion tank as part of an overall maintenance plan can prevent you from getting stranded from a sudden failure later on. From 1974 to 2019, Bavarian Autosport was one of the premier vendors for BMW and MINI auto parts. We are happy to preserve the Bav Auto legacy by continuing to carry their high-quality products into the future. All Bav Auto parts will remain unchanged in design and sourced from the same OEM suppliers to ensure long-lasting reliability. We trust these parts, accessories, and upgrades so confidently that we back every Bavarian Autosport branded component with a 2-year warranty.
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Genuine BMW Expansion Tank Cap - E3X / E53 / Z4
Genuine BMW Expansion Tank Cap - E3X / E53 / Z4
Genuine BMW - Corporate Logo
T#:207187
Part#: 17117639022
In Stock
21% off MSRP $ 34.96

MSRP stands for Manufacturer's Suggested Retail Price. This is the suggested retail price provided by the manufacturer, supplier or seller.

$ 27.67 USD
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21% off MSRP
$ 34.96

MSRP stands for Manufacturer's Suggested Retail Price. This is the suggested retail price provided by the manufacturer, supplier or seller.

$ 27.67 USD
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Genuine BMW Radiator Cap - 2,0Bar
This item fits the following BMW Chassis:
E36 M3,E39 M5,E46 M3,E85 Z4M,E53 48IS,E36,E38,E39,E46,E53 X5,E65,E83 X3,E85 Z4,E86 Z4,F06,F10,F12,F13

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Bav Auto Expansion Tank Mounting Plate - E46 Non-M w/ Manual Trans
Bav Auto Expansion Tank Mounting Plate - E46 Non-M w/ Manual Trans ...
For vehicles with a manual transmission only
10X Entries Into Our F80 M3 Sweepstakes
Bavarian Autosport - Corporate Logo
T#:638088
Part#: 17111436250
In Stock
Sale - Save 20% $ 44.99

This product was last offered at the strikethrough price on
05-03-2026

$ 35.99 USD
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Sale - Save 20%
$ 44.99

This product was last offered at the strikethrough price on
05-03-2026

$ 35.99 USD
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This Bav Auto part is the mounting bracket from the radiator to the expansion tank on an E46 3 series with a Manual Transmission. From 1974 to 2019, Bavarian Autosport was one of the premier vendors for BMW and MINI auto parts. We are happy to preserve the Bav Auto legacy by continuing to carry their high-quality products into the future. All Bav Auto parts will remain unchanged in design and sourced from the same OEM suppliers to ensure long-lasting reliability. We trust these parts, accessories, and upgrades so confidently that we back every Bavarian Autosport branded component with a 2-year warranty.
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Genuine BMW Coolant Expansion Tank - E53 X5, E46 M52/54, E83 X3
Genuine BMW Coolant Expansion Tank - E53 X5, E46 M52/54, E83 X3 ...
Genuine BMW - Corporate Logo
T#:360752
Part#: 17117573781
In Stock
$ 173.21 USD
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$ 173.21 USD
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We have found that the expansion tanks should be replaced based on age as well as condition. Expansion tanks seem to have a lifespan of less than six years before they show signs of fatigue and wear. Pre-emptively replacing the expansion tank as part of an overall maintenance plan can prevent you from getting stranded from a sudden failure later on.
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Genuine BMW Coolant Expansion Tank - E46 M3
Genuine BMW Coolant Expansion Tank - E46 M3
Genuine BMW - Corporate Logo
T#:13185
Part#: 17112283344
In Stock
7% off MSRP $ 215.23

MSRP stands for Manufacturer's Suggested Retail Price. This is the suggested retail price provided by the manufacturer, supplier or seller.

$ 199.98 USD
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7% off MSRP
$ 215.23

MSRP stands for Manufacturer's Suggested Retail Price. This is the suggested retail price provided by the manufacturer, supplier or seller.

$ 199.98 USD
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This radiator coolant reservoir/expansion tank for E46 M3 is a common failure item as the plastic weakens over time and stress crack will lead to coolant leaks. If your car has over 80k miles and hasn't had one of these replaced, we highly recommend it during your next major service. We have found that the aftermarket coolant reservoirs fail easier than the original BMW piece so we only offer the BMW type on this part.

When doing any sort of repair or maintenance there is no replacement for genuine factory parts. Turner Motorsport carries the Genuine BMW brand with pride and has the parts you need to complete your next project with confidence.

This item fits the following BMWs:
2001-2006 E46 BMW M3
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Bav Auto Expansion Tank Mounting Plate - E46 Non-M w/ Auto Trans
Bav Auto Expansion Tank Mounting Plate - E46 Non-M w/ Auto Trans ...
For vehicles with an automatic transmission only
10X Entries Into Our F80 M3 Sweepstakes
Bavarian Autosport - Corporate Logo
T#:638089
Part#: 17111436251
In Stock
Sale - Save 20% $ 45.99

This product was last offered at the strikethrough price on
05-03-2026

$ 36.79 USD
Free Shipping on orders $49 and up
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Sale - Save 20%
$ 45.99

This product was last offered at the strikethrough price on
05-03-2026

$ 36.79 USD
Free Shipping on orders $49 and up
Add to Wish List
This Bav Auto part is the mounting bracket from the radiator to the expansion tank on E46 3 series and E85/E86 Z4 with an Automatic Transmission. From 1974 to 2019, Bavarian Autosport was one of the premier vendors for BMW and MINI auto parts. We are happy to preserve the Bav Auto legacy by continuing to carry their high-quality products into the future. All Bav Auto parts will remain unchanged in design and sourced from the same OEM suppliers to ensure long-lasting reliability. We trust these parts, accessories, and upgrades so confidently that we back every Bavarian Autosport branded component with a 2-year warranty.
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Rein Coolant Expansion Tank - E46, E53, E83
Rein Coolant Expansion Tank - E46, E53, E83
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:402141
Part#: 17117573781
In Stock
$ 76.39 USD
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$ 76.39 USD
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Includes cap and level sensor
Genuine BMW - Expansion Tank Replacement Kit - Level 1
Genuine BMW - Expansion Tank Replacement Kit - Level 1
Genuine BMW - Corporate Logo
T#:374557
Part#: 17117573781OEKT
In Stock
$ 273.99 USD
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$ 273.99 USD
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The expansion tank in your BMW is a vital component of the cooling system, and because of the constant abuse from heat and temperature changes, it often fails. This kit contains all of the basic items needed for a tank replacement.
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Expansion Tank Mounting Bracket - E46 - Manual Trans
Expansion Tank Mounting Bracket - E46 - Manual Trans
For vehicles with manual transmission only
Genuine BMW - Corporate Logo
T#:13180
Part#: 17111436250
Ships in 3 Business Days
2% off MSRP $ 134.99

MSRP stands for Manufacturer's Suggested Retail Price. This is the suggested retail price provided by the manufacturer, supplier or seller.

$ 131.99 USD
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2% off MSRP
$ 134.99

MSRP stands for Manufacturer's Suggested Retail Price. This is the suggested retail price provided by the manufacturer, supplier or seller.

$ 131.99 USD
Free Shipping
Add to Wish List
This Genuine BMW part is the mounting bracket from the radiator to the expansion tank on E46 3 series Manual Transmission.

When doing any sort of repair or maintenance there is no replacement for genuine factory parts. Turner Motorsport carries the Genuine BMW brand with pride and has the parts you need to complete your next project with confidence.​

This item fits the following BMWs:
1999-2005 E46 BMW 323i 323ci 325i 325ci 325xi 328i 328ci 330i 330ci 330xi
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Genuine BMW Cap - 17121719356 - E30,E46,E46 M3
Genuine BMW Cap - 17121719356 - E30,E46,E46 M3
Genuine BMW - Corporate Logo
T#:46115
Part#: 17121719356
Ships in 6 Business Days
3% off MSRP $ 31.99

MSRP stands for Manufacturer's Suggested Retail Price. This is the suggested retail price provided by the manufacturer, supplier or seller.

$ 30.99 USD
Free Shipping on orders $49 and up
Add to Wish List
3% off MSRP
$ 31.99

MSRP stands for Manufacturer's Suggested Retail Price. This is the suggested retail price provided by the manufacturer, supplier or seller.

$ 30.99 USD
Free Shipping on orders $49 and up
Add to Wish List


Genuine BMW Cap
This item fits the following BMW Chassis:
E46 M3,E30,E46

Fits BMW Engines including:
M20,S54,S62

Expansion Tank Mounting Plate
Expansion Tank Mounting Plate
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:402140
Part#: 17111436250
In Stock
$ 70.99 USD
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$ 70.99 USD
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Expansion Tank Mounting Bracket - E46 E85 Z4 - Auto Trans
Expansion Tank Mounting Bracket - E46 E85 Z4 - Auto Trans
For vehicles with automatic transmission only
Genuine BMW - Corporate Logo
T#:12560
Part#: 17111436251
In Stock
Sale - Save 51% $ 205.99

MSRP stands for Manufacturer's Suggested Retail Price. This is the suggested retail price provided by the manufacturer, supplier or seller.

$ 101.32 USD
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Sale - Save 51%
$ 205.99

This product was last offered at the strikethrough price on
05-07-2026

$ 101.32 USD
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This Genuine BMW part is the mounting bracket from the radiator to the expansion tank on E46 3 series and E85/E86 Z4 with Automatic Transmission.

When doing any sort of repair or maintenance there is no replacement for genuine factory parts. Turner Motorsport carries the Genuine BMW brand with pride and has the parts you need to complete your next project with confidence.

This item fits the following BMWs:
1999-2005 E46 BMW 323i 323ci 325i 325ci 325xi 328i 328ci 330i 330ci 330xi
2003-2008 E85 BMW Z4 2.5i Z4 3.0i Z4 3.0si
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Rein Expansion Tank Mounting Plate - E46, Z4
Rein Expansion Tank Mounting Plate - E46, Z4
For vehicles with automatic transmission only
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:402139
Part#: 17111436251
Ships in 1 Business Day
$ 80.99 USD
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$ 80.99 USD
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Mounts to the side of the radiator for retaining the expansion tank
Bremmen Coolant Bleeder Screw - BMW E30 E36 E38 E39 E46 E83 E90 Z4
Bremmen Coolant Bleeder Screw - BMW E30 E36 E38 E39 E46 E83 E90 Z4 ...
10X Entries Into Our F80 M3 Sweepstakes
Bremmen Parts - Corporate Logo
T#:640140
Part#: 17111712788
Ships on Sep 16, 2026
$ 3.99 USD
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$ 3.99 USD
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Plastic bleeder screw for cooling system is used to bleed air that would otherwise create an air pocket and lead to overheating. Includes o-ring seal.
Bav Auto Expansion Tank Cap - E36 E46 E34 E39 E32 E38 E65 X3 X5 Z4
Bav Auto Expansion Tank Cap - E36 E46 E34 E39 E32 E38 E65 X3 X5 Z4 ...
10X Entries Into Our F80 M3 Sweepstakes
Bavarian Autosport - Corporate Logo
T#:640208
Part#: 17117639022
In Stock
Sale - Save 15% $ 13.99

This product was last offered at the strikethrough price on
06-03-2026

$ 11.89 USD
Free Shipping on orders $49 and up
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Sale - Save 15%
$ 13.99

This product was last offered at the strikethrough price on
06-03-2026

$ 11.89 USD
Free Shipping on orders $49 and up
Add to Wish List
This radiator expansion tank cap is used most BMW's from 1991-2006. It is a common failure item. When this item fails, it cannot hold pressure which results in your BMW overheating. If you are overhauling your coolant system, now is the time to consider preventative replacing this cap. It is also referred to as the coolant reservoir cap. From 1974 to 2019, Bavarian Autosport was one of the premier vendors for BMW and MINI auto parts. We are happy to preserve the Bav Auto legacy by continuing to carry their high-quality products into the future. All Bav Auto parts will remain unchanged in design and sourced from the same OEM suppliers to ensure long-lasting reliability. We trust these parts, accessories, and upgrades so confidently that we back every Bavarian Autosport branded component with a 2-year warranty.
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OEM Rein Expansion Tank Cap - BMW E32 E34 E36 E38 E39 E46 & More
OEM Rein Expansion Tank Cap - BMW E32 E34 E36 E38 E39 E46 & More ...
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:340541
Part#: 17111742231
Ships in 1 Business Day
$ 17.99 USD
Free Shipping on orders $49 and up
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$ 17.99 USD
Free Shipping on orders $49 and up
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This radiator expansion tank cap is used most BMW's from 1991-2006. It is a common failure item. When this item fails, it cannot hold pressure which results in your BMW overheating. If you are overhauling your coolant system, now is the time to consider preventative replacing this cap. It is also referred to as the coolant reservoir cap.
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Genuine BMW - Level 1 Expansion Tank Replacement Kit - E46 M52,M54
Genuine BMW - Level 1 Expansion Tank Replacement Kit - E46 M52,M54 ...
Genuine BMW - Corporate Logo
T#:380426
Part#: 17117573781OEKT1
Ships in 3 Business Days
$ 589.99

This product was last offered at the strikethrough price on
07-10-2026

$ 499.99 USD
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$ 499.99 USD
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